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1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef __LINUX_MUTEX_TYPES_H | |
3 | #define __LINUX_MUTEX_TYPES_H | |
4 | ||
5 | #include <linux/atomic.h> | |
6 | #include <linux/lockdep_types.h> | |
7 | #include <linux/osq_lock.h> | |
8 | #include <linux/spinlock_types.h> | |
9 | #include <linux/types.h> | |
10 | ||
11 | #ifndef CONFIG_PREEMPT_RT | |
12 | ||
13 | /* | |
14 | * Simple, straightforward mutexes with strict semantics: | |
15 | * | |
16 | * - only one task can hold the mutex at a time | |
17 | * - only the owner can unlock the mutex | |
18 | * - multiple unlocks are not permitted | |
19 | * - recursive locking is not permitted | |
20 | * - a mutex object must be initialized via the API | |
21 | * - a mutex object must not be initialized via memset or copying | |
22 | * - task may not exit with mutex held | |
23 | * - memory areas where held locks reside must not be freed | |
24 | * - held mutexes must not be reinitialized | |
25 | * - mutexes may not be used in hardware or software interrupt | |
26 | * contexts such as tasklets and timers | |
27 | * | |
28 | * These semantics are fully enforced when DEBUG_MUTEXES is | |
29 | * enabled. Furthermore, besides enforcing the above rules, the mutex | |
30 | * debugging code also implements a number of additional features | |
31 | * that make lock debugging easier and faster: | |
32 | * | |
33 | * - uses symbolic names of mutexes, whenever they are printed in debug output | |
34 | * - point-of-acquire tracking, symbolic lookup of function names | |
35 | * - list of all locks held in the system, printout of them | |
36 | * - owner tracking | |
37 | * - detects self-recursing locks and prints out all relevant info | |
38 | * - detects multi-task circular deadlocks and prints out all affected | |
39 | * locks and tasks (and only those tasks) | |
40 | */ | |
41 | struct mutex { | |
42 | atomic_long_t owner; | |
43 | raw_spinlock_t wait_lock; | |
44 | #ifdef CONFIG_MUTEX_SPIN_ON_OWNER | |
45 | struct optimistic_spin_queue osq; /* Spinner MCS lock */ | |
46 | #endif | |
47 | struct list_head wait_list; | |
48 | #ifdef CONFIG_DEBUG_MUTEXES | |
49 | void *magic; | |
50 | #endif | |
51 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
52 | struct lockdep_map dep_map; | |
53 | #endif | |
54 | }; | |
55 | ||
56 | #else /* !CONFIG_PREEMPT_RT */ | |
57 | /* | |
58 | * Preempt-RT variant based on rtmutexes. | |
59 | */ | |
60 | #include <linux/rtmutex.h> | |
61 | ||
62 | struct mutex { | |
63 | struct rt_mutex_base rtmutex; | |
64 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
65 | struct lockdep_map dep_map; | |
66 | #endif | |
67 | }; | |
68 | ||
69 | #endif /* CONFIG_PREEMPT_RT */ | |
70 | ||
71 | #endif /* __LINUX_MUTEX_TYPES_H */ |